Avast giving error while starting in gui or command line like this
$ avast: can not initialize avast! engine: Invalid argument

solve this by typing this as root in command line.$ sysctl -w kernel.shmmax=100000000

Reason?
older kernels have an artificial limitations which dictates the maximum size of one SHM block in bytes. And, one block of our database exceeded this limit. so just, relax them to more reasonable values. that’s it